Bacterioplankton Activity in a Meso-eutrophic Subtropical Coastal Lagoon

The aim of this study was to investigate whether the bacterioplankton activity in the meso-eutrophic Conceição Lagoon would increase significantly under allochthonous inputs of inorganic nutrients and organic carbon. Abundance and biomass of bacterioplankton were evaluated under three treatments: li...

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Main Authors: Maria L. Schmitz Fontes, Heloísa Fernandes, Manoela Brandão, Mariana Coutinho Hennemann, Raquel Aparecida Loss, Valdelúcia Maria Alves de Souza Grinevicius, Denise Tonetta, Karina Cesca, Mônica Hessel Silveira, Mara Bedin, Derce Recouvreux, Regina Vasconcellos Antônio
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:International Journal of Microbiology
Online Access:http://dx.doi.org/10.1155/2018/3209605
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Summary:The aim of this study was to investigate whether the bacterioplankton activity in the meso-eutrophic Conceição Lagoon would increase significantly under allochthonous inputs of inorganic nutrients and organic carbon. Abundance and biomass of bacterioplankton were evaluated under three treatments: light (14 h light/10 h dark), complete darkness (dark-control), and nutrient (C + N + P—dark, 100 : 10 : 1) enrichments during 72 h. Nutrient enrichments promoted a significant increase in abundance (maximum of 19.0 ×109 cells·L−1 in the first 32 hours) and biomass of the heterotrophic bacterioplankton, which induced the formation of large clusters. Bacterial biomass remained constant in the non-enriched incubations (dark-control and light). Bacterial growth rates were significantly higher after nutrient additions (1.35 d−1), followed by control (0.79 d−1), and light (0.63 d−1) treatments, which were statistically equal (p>0.05). Bacterial production rates were also significantly higher under nutrient additions (1.28 d−1), compared to the control and light (0.50 d−1 and 0.44 d−1, respectively), demonstrating that bacterial growth and production in this meso-eutrophic lagoon are under an immediate “bottom-up” regulation, followed by a potential top-down effect. These facts reinforce the urgency on improving the local wastewater management plan in order to prevent further expansion of anoxic waters.
ISSN:1687-918X
1687-9198